selftests/user_events: Add non-spacing separator check

The ABI documentation indicates that field separators do not need a
space between them, only a ';'. When no spacing is used, the register
must work. Any subsequent register, with or without spaces, must match
and not return -EADDRINUSE.

Add a non-spacing separator case to our self-test register case to ensure
it works going forward.

Link: https://lore.kernel.org/linux-trace-kernel/20240423162338.292-3-beaub@linux.microsoft.com



Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>